New leaders often fail by trying to mimic their mentors, resulting in a mediocre "C+ version" of someone else. True excellence comes from giving yourself permission to be an "A+ version" of yourself. Trusting that your unique, authentic style is "enough" is the key to unlocking your full leadership potential.

A leader focused solely on personal wins creates a toxic environment that ultimately leads to their own apathy and burnout. They become disconnected from the very machine they built, creating a job they personally loathe despite their apparent success.

Renfrew was hired as CEO to bring financial discipline to a creative founder's brand. She was ultimately fired by messenger because the founder, who still saw herself as the boss, wasn't ready to accept profit-driven decisions that clashed with her creative vision.

Treat mentors as a collection of traits, not a monolithic influence. Actively adopt the qualities you admire while consciously rejecting the ones that don't align with your goals. A person can be a great role model for one area of life but a poor one for another.

A demeaning boss early in her career provided the motivation to rise to a leadership position to ensure others were treated with respect. This reframes a negative experience as a foundational career catalyst, providing the 'fire' to drive progress.

Exposure to incompetent or arrogant people early in a career provides a powerful, negative blueprint for future leadership. By observing their detrimental behaviors, junior professionals can create a mental model of what to avoid when they gain authority, learning how not to negatively impact their own teams.

The command-and-control style personified by Miranda Priestly is no longer viable. Today's workplace has numerous accountability channels, like leaked meeting recordings and social media scrutiny, that quickly expose and penalize toxic environments.

Working for a difficult manager provides invaluable, albeit painful, lessons. It creates a strong mental model of negative leadership traits, helping you consciously decide not to replicate that behavior in your own management style.

Not all leaders are inspirational. MongoDB's Cedric Pech suggests that while great managers show you what to do, bad managers offer an even more visceral lesson: what to avoid at all costs. The pain from working under a poor leader creates a powerful, lasting template for the kind of leader you never want to become.